A tonometer is the instrument that is used to measures the pressure (intraocular pressure or IOP) inside the eyes. Tonometry is a common and standard test in a comprehesive eye health examination.  There are many different types of tonometers that measure eye pressure using many different methods.  The "gold standard" tonometer is the Goldmann Applanation Tonometer, but this tonometer requires that the patient's eyes be anesthetized (numbed) using eye drops and then the patient must keep their eye open while a small probe is pressed gently against the eye.  Because this is difficult for most patients, non-invasive tonometers like the Non-Contact Tonometer (NCT or "Air Puff") are more frequently used.  The NCT measures eye pressure by blowing only air at the eye.

What is Glaucoma?

Glaucoma is a completely painless disease that has no symptoms or warning signs so it is often called the "silent thief of sight." Because there are no outward symptoms, it is important to get a COMPREHENSIVE eye HEALTH exam annually to check for any signs of glaucoma.  Glaucoma falls into four main types:

1) Open Angle Glaucoma: Open Angle Glaucoma happens when the eye does not drain fluid as well as it should, the eye pressure rises and starts to damage the optic nerve and nerve fiber layers of the retina. 

2) Normal Tension Glaucoma:  This type of glaucoma occurs when a patient with "normal" eye pressure has sensitive optic nerves and still develops glaucoma damage over time.  

3) Narrow Angle/Chronic Angle Closure Glaucoma: This type of glaucoma occurs when a person's "angle" (the area where the fluid drains) is narrow so the fluid does not have much room to drain, the eye pressure rises and starts to damage the optic nerve and nerve fiber layers of the retina.  Again because there are few or no outward symptoms, it is important to get a COMPREHENSIVE eye HEALTH exam annually to check for any signs of glaucoma. 

4) Secondary Glaucomas:  Secondary glaucoma is the name used to describe glaucomas that occur as a side effect or “secondary” to another underlying medical condition or trauma.

  • Pigmentary Glaucoma: This secondary glaucoma results from Pigmentary Dispersion Syndrome and occurs when the pigment rubs off of the iris and subsequently raises eye pressure causing damage to the optic nerve and nerve fiber layers of the retina. 
  • Pseudoexfoliation Glaucoma: Pseudoexfoliation occurs when the edge of the lens starts to flake away like dandruff, they clog up the trabecular meshwork and stop the aqueous fluid from draining efficiently raising eye pressure and damage the optic nerve and nerve fiber layers of the retina. This condition tends to be more common in older people and in people of Scandinavian and Southern Mediterranean origin.
  • Uveitic Glaucoma: Uveitis occurs when a part of the eye called the uvea becomes swollen and inflamed. If uveitis leads to increased pressure, we get uveitic glaucoma.
  • Neovascular Glaucoma: Neovascular (“new blood vessels”) glaucoma occurs when poor blood supply within the eye causes new blood vessels to grow on the surface of the eye and into the drainage channel. The new blood vessels can cause eye pressure to rise by blocking the outflow of aqueous fluid. This type of glaucoma is usually associated with other eye conditions like diabetic retinopathy.
  • Steroid-Induced Glaucoma: Medicine-related secondary glaucoma is the result of inflammation caused by medication, typically steroids. Steroids are used for a variety of medical conditions and can be inhaled (inhalers), taken orally as tablets, injected or applied directly to the skin or eye. They are an important type of medicine, but a possible side effect is increased eye pressure. This effect is called ‘steroid response’.
  • Trauma Induced Glaucoma: Trauma can mean either a blow to the eye, a penetrating injury (when something pierces the eye) or a chemical injury (such as an alkali burn). It can happen immediately after the injury or develop over time. Blunt trauma (such as a blow to the eye) can affect the shape of the eye, meaning the pressure builds up over several years. People affected will need to be monitored to limit the chance of developing glaucoma in the future.
  • Iatrogenic Glaucoma: Iatrogenic literally means ‘caused by a doctor’ and unfortunately this is one of the most common reasons people experience secondary rises in eye pressure. The main iatrogenic cause is following retinal surgery. During retinal surgery, the surgeon may need to put gas or silicone oil in the eye. These substances can have the side effect of raising the eye pressure. 

Most of the time, glaucoma develops very slowly which means that many people don’t realize that they are affected until some damage to their vision has already occurred. However, occasionally a person can have an Angle Closure Glaucoma "attack," their already narrow angles close, the fluid can no longer drain and the pressure in the eyes can rise drastically causing sudden and severe or complete vision loss.  An Angle Closure Glaucoma attack can develop quickly, and symptoms do occur, especially when going from a dark environment into light. These can include:  

  • Red eyes
  • Intense headaches
  • Tenderness around the eyes
  • Eye pain
  • Seeing rings/halos around lights
  • Blurred vision
  • Nausea and vomiting

**If you notice any of these symptoms, it’s important to CALL DR. KUBOTA'S OFFICE RIGHT AWAY so that you can be examined as soon as possible. If the office is closed, please go IMMEDIATELY to the nearest emergency room and ask to see the ophthalmologist on call.**

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